The present disclosure relates to semiconductor devices. Semiconductor devices may trend toward higher integration, higher density, lower power consumption, and faster operating speeds. A semiconductor device with highly integrated circuits may include a multi-layered interconnection structure, which may be formed of a metal material (e.g., aluminum). For example, the formation of aluminum interconnection lines may include depositing an aluminum layer on an insulating layer and etching it to expose the insulating layer.
The use of copper, instead of aluminum, as a material for interconnection lines, may increase as a design rule of semiconductor devices decreases. This may be due to the relatively high electrical resistivity of aluminum. For example, as a width of an aluminum line decreases, its resistance increases, and thus it may be a difficult to realize semiconductor devices with higher operating speeds. Copper may offer advantages in cost and electrical conductivity, but there may be difficulty in patterning a copper layer using an etching technique. A damascene process may also be used to form copper interconnection lines.
Further, due to the increasing integration density of semiconductor devices, a space between interconnection lines may become narrower and narrower, and this may cause electrical interference between interconnection lines and a delay in a signal transfer speed, despite the use of copper interconnection lines.